Two leg walking humanoid robot

ABSTRACT

A biped walking humanoid robot is disclosed having an arrangement whereby shocks acting on various parts of the robot when it falls can be relieved and its state of fall can then be detected. The robot has a body ( 11 ) capable of bending forward, a pair of legs ( 12 L,  12 R) attached to a lower part of the body at a pair of opposite sides thereof, respectively, a pair of arms ( 13 L,  13 R) attached to an upper part of the body at a pair of opposite sides, respectively, and a head ( 14 ) attached to an upper end of the body, each of the legs having a upper leg ( 15 L,  15 R) attached to the body so as to be pivotally movable relative thereto triaxially, a lower leg ( 16 L,  16 R) attached to a lower end of the upper leg so as to be pivotally movable relative thereto monoaxially and a foot ( 17 L,  17 R) attached to a lower end of the lower leg so as to be pivotally movable relative thereto biaxially, each of the arms having an upper arm ( 25 L,  25 R) attached to the body so as to be pivotally movable relative thereto biaxially, a lower arm ( 26 L,  26 R) attached to the upper arm so as to be pivotally movable relative thereto monoaxially and a hand ( 27 L,  27 R) attached to the lower hand so as to be pivotally movable relative thereto biaxially, the robot also having drive means ( 23 L,  23 R,  24 L,  24 R;  21 L,  21 R;  19 L,  19 R,  20 L,  20 R,  18 L,  18 R; . . . ) associated with the feet, the lower legs and the upper legs of the legs, the hands, the lower arms and the upper arms of the arms and a body bending-forward region for pivotally moving them, respectively, a control stage (51) for controlling driving actions of the drive means, and a contact detector (40) mounted at each of an outer elbow surface area formed between the upper and lower arms, and an outer wrist surface area between the lower arm and the hand of each of the arms, and a lower toe surface area of the foot, a lower heal surface area of the foot, an outer knee surface area between the upper and lower legs of each of the legs, and a hip surface area and a back surface area of the body, the contact detector at each of these surface areas comprising a casing portion ( 41 ) made of a material forming an outer covering surface area of the robot, a pressure sensor ( 42 ) for sensing a pressure acting on the casing portion and a shock absorbing material ( 43 ) for absorbing a shock acting on the casing portion. Thus, when the biped walking humanoid robot is having a fall, the state or type of this fall can be determined by the control stage in response to a contact signal detected by the pressure sensor in the contact detector at a relevant part of the abovementioned robot parts which is brought into contact with the floor or ground. Then, on the basis of the type of the fall determined, the control stage is allowed to act on the drive means to move the arm and leg parts suitably so as to cause the robot to take a corrective falling action to have a safety fall and then to move to taking a rising action to get up on its feet.

TECHNICAL FIELD

[0001] The present invention relates to a biped (two-footed) walkinghumanoid robot and, in particular, to a biped walking humanoid robotwhich is so designed that shocks acting on various parts of the robotwhen it falls can be relieved and its state or type of fall can then bedetected.

BACKGROUND ART

[0002] A biped walking robot as it is called in the art has so far beenmade able to walk with two legs by producing in advance data for apre-established walking pattern (hereinafter referred to as “gait”) andactuating the legs in a controlled manner in accordance with the gaitdata so that the robot can bipedally walk as desired.

[0003] Such a conventional biped walking robot tends to become unstablein walking position due, for example, to floor or ground surfaceconditions and an error in the physical parameters of the robot itselfand may then even turn over or fall violently.

[0004] However, while conventional biped walking humanoid robots aredesigned to fall as little as possible, they have never been designed sothey when falling down take a safety way of falling down or then toscramble on their feet. To wit, no biped walking humanoid robot has beenbuilt having the capability of relieving shocks acting on its parts orthe capability of detecting a particular state that it is falling.Further, if the conventional biped humanoid robot that fell down shouldbe allowed to rise on its feet, the fact that the outer covering surfaceareas of its trunk body, legs and arms are desirably formed ofrelatively flat surfaces makes it hard to have the robot take successiveactions dynamically and with smoothness for it to rise. This problemalso applies if the conventional biped humanoid should be allowed tomake a forward roll.

[0005] It is accordingly an object of the present invention to provide abiped walking humanoid robot having the capability of relieving shocksacting on its various parts when it falls violently and also thecapability of detecting a particular state that it is falling.

DISCLOSURE OF THE INVENTION

[0006] In order to attain the object mentioned above, there is providedin accordance with the present invention a biped walking humanoid robot,which includes a body portion having an upper and a lower part, a pairof leg portions attached to the lower part of the body portion at a pairof its opposite sides, respectively, a pair of arm portions attached tothe upper part of the body portion at a pair of its opposite sides,respectively, and a head portion attached to an upper end of the upperpart of the body portion, wherein each of the leg portions includes towupper leg portions attached to the lower part of the body portion so asto be pivotally movable relative thereto triaxially, a lower leg portionattached to the upper leg portion so as to be pivotally movable relativethereto monoaxially, and a foot portion attached to the lower legportion so as to be pivotally movable relative thereto biaxially,wherein each of the arm portions includes two upper arm portionsattached to the upper part of the body portion so as to be pivotallymovable relative thereto biaxially, a lower arm portion attached to theupper arm portion so as to be pivotally movable relative theretomonoaxially, and a hand portion attached to the lower arm portion so asto be pivotally movable relative thereto biaxially, wherein the bodyportion has an intermediate, anteflex region at which it is made able tobend forward; and wherein the robot further comprises a drive means forpivotally moving each of the foot portion, the lower leg portion and theupper leg portion of each of the leg portions, and the hand portion, thelower arm portion and the upper arm portion of each of the arm portions,and the body portion at the anteflex region, and a control means forcontrolling driving actions of the drive means; the robot beingcharacterized in that there is provided a contact detector at each of anouter area of an elbow portion formed between the upper and lower armportions, and an outer area of a wrist portion formed between the lowerarm portion and the hand portion of each of the said arm portions, and alower side of a toe portion formed in the foot portion, a lower side ofa heel portion formed in the foot portion, and an outer area of a kneeportion formed between the upper and lower leg portions of each of thesaid leg portions, and a hip region and a back region of said bodyportion, and that the said contact detector comprises a casing portionforming an outer covering surface of the robot at the said contactdetector, a pressure sensor for sensing a pressure acting on the saidcasing portion and an impact absorbing material for relieving a shockacting on the said casing portion.

[0007] A biped walking humanoid robot according to the present inventionis preferably so configured in each of such contact detectors that thesaid pressure sensor and the said impact absorbing material areintegrally formed and more preferably that the said casing portion, thesaid pressure sensor and the said impact absorbing material are formedintegrally. A biped walking humanoid robot according to the presentinvention is also preferably so configured in each of such contactdetectors that the said casing portion lies at an outermost sidethereof, or that the said pressure sensor lies at an outermost sidethereof, or that the said impact absorbing material lies at an outermostside thereof.

[0008] A biped walking humanoid robot according to the present inventionis preferably so configured that each of the aid body portion, the upperand lower arm portions of the said arm portions, and the upper and lowerleg portions of the said leg portions has a curved outer coveringsurface that is convex in contour.

[0009] A biped walking humanoid robot according to the present inventionis preferably so configured that for each of the said leg portions, thesaid foot portion is made pivotally movable relative to the said lowerleg portion in a pitch direction in a range of angles from −20 to +20degrees or more, the said lower leg portion is made pivotally movablerelative to the said upper leg portion in a pitch direction in an rangeof angles from 0 to +60 degrees or more, and the said upper leg portionis made pivotally movable relative to said body portion in a pitchdirection in a range of angles from 0 to +45 degrees or more, and thesaid body portion is made able to bend forward in a range of angles from0 to +30 degrees or more.

[0010] A biped walking humanoid robot according to the present inventionis preferably so configured that those of the said drive means forpivotally moving the foot portion, the lower leg portion and the upperleg portion of each of the said leg portions, respectively, are disposedinclined to one another so as not to hinder pivotal movements of thesaid foot portion, the said upper portion and the said lower legportions.

[0011] With a biped walking humanoid robot constructed as mentionedabove, namely so that a contact detector having an impact absorbingmaterial is disposed at each of those parts of the robot which can hiton the floor or ground when the robot is falling down to or rolling overit, that is, at each of an outer area of an elbow portion formed betweenthe upper and lower arm portions, and an outer area of a wrist portionformed between the lower arm portion and the hand portion of each of thearm portions, and a lower side of a toe portion formed in the footportion, a lower side of a heel portion formed in the foot portion, andan outer area of a knee portion formed between the upper and lower legportions of each of the said leg portions, and a hip region and a backregion of the body portion, any shock acting on any of these partshitting on the floor or ground can be absorbed by the impact absorbingmaterial. With the shock against the internal structure of each of theseparts so alleviated, they are protected from any possible damage thatshould otherwise be the case when the biped walking humanoid robothappens to fall to or is attempting to perform a rolling action over thefloor or ground.

[0012] And, when the biped walking humanoid robot is having a fall, thestate or type of this fall can be determined by the control means inresponse to a contact signal detected by the pressure sensor in thecontact detector at a relevant part of the abovementioned robot partswhich is brought into contact with the floor or ground. Then, on thebasis of the type of the fall determined, the control means is allowedto act on the drive means to move the arm and leg parts suitably so asto cause the robot to take a corrective falling action to have a safetyfall and then to move to taking a rising action to get up on its feet.

[0013] Forming integrally the pressure sensor and the impact absorbingmaterial, or the casing portion, the pressure sensor and the impactabsorbing material, in each of the contact detectors allows each contactdetector to be simplified in makeup and to be readily assembled.

[0014] In each contact detector, disposing the casing portion at theoutermost side is advantageous in that when the biped walking humanoidrobot falls to cause the contact detector to hit on the floor or ground,the casing comes into direct contact with the floor or ground, therebyprotecting the pressure sensor, the impact resistant material andfurther the inner structure of the robot from the shock.

[0015] In each contact detector, disposing the pressure sensor at theoutermost side is advantageous in that when the biped walking humanoidrobot falls, the pressure sensor comes into direct contact with thefloor or ground, thereby making most certain of sensing the pressurecontact of the contact detector with the floor or ground.

[0016] In each contact detector, disposing the impact absorbing materialat the innermost side is advantageous in that when the biped walkinghumanoid robot falls to cause the contact detector to hit on the flooror ground, the impact absorbing material comes into direct contact withthe floor or ground, thereby making for most certain of absorbing theshock.

[0017] Making each of the body portion, the upper and lower arms of thearm portions, and the upper and lower leg portions of the leg portionsof a curved outer covering surface that is convex in contour allows thebiped humanoid robot in its rising action from the state of a fall tosmoothly rise with the aid of such curved outer covering surfaces incontact with the floor or ground.

[0018] If for each of the said leg portions, the foot portion is madepivotally movable relative to the lower leg portion in a pitch directionin a range of angles between −20 and +20 degrees, the lower leg portionis made pivotally movable relative to the upper leg portion in a pitchdirection in an range of angles between 0 and +60 degrees, and the upperleg portion is made pivotally movable relative to body portion in apitch direction in a range of angles between 0 and +45 degrees, and thebody portion is made able to bend forward in a range of angles between 0and +30 degrees, the biped humanoid robot in its rising action of thestate of a fall is allowed to rise for certain by virtue of theseangular ranges of movements given.

[0019] If those of the drive means for pivotally moving the footportion, the lower leg portion and the upper leg portion of each of theleg portions are disposed inclined to one another so as not to hinderpivotal movements of the foot portion, the upper leg portion and thelower leg portion, the biped humanoid robot in its rising action fromthe state of a fall is allowed to rise for certain by virtue of the factthat the foot portion, the lower leg portion and the upper leg portionof each of the leg portions are prevented in their respective pivotalmovements from interfering with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will better be understood from thefollowing detailed description and the drawings attached hereto showingcertain illustrative forms of embodiment of the present invention. Inthis connection, it should be noted that such forms of embodimentillustrated in the accompanying drawings hereof are intended in no wayto limit the present invention but to facilitate an explanation andunderstanding thereof. In the drawings:

[0021]FIG. 1 shows an external appearance of a biped walking humanoidrobot according to the present invention as one form of embodimentthereof, wherein FIG. 1A and FIG. 1B are a schematic front and aschematic side elevation view thereof, respectively;

[0022]FIG. 2 is a schematic diagram illustrating a mechanical makeup ofthe biped walking humanoid robot shown in FIG. 1;

[0023]FIG. 3 is an enlarged perspective view illustrating a contactdetector as it is decomposed, in the biped walking humanoid robot shownin FIG. 1;

[0024]FIG. 4 is a schematic view illustrating respective angular limitsof pivotal forward movements of the body portion at an anteflex region,and the upper and lower legs and the foot of each of the legs abouttheir respective joints of the biped walking humanoid robot shown inFIG. 1;

[0025]FIG. 5 is a schematic view illustrating respective angular limitsof pivotal forward (backward) movements of the body portion at theanteflex region, and the upper and lower legs and the foot of each ofthe legs about their respective joints of the biped walking robot shownin FIG. 1;

[0026]FIG. 6 shows a preferred layout of joint drive motors for each ofthe legs of the biped walking humanoid robot shown in FIG. 1, whereinFIGS. 6A and 6B are schematic diagrams illustrating their positionstaken when the robot stands upright and has pivotal movements producedthereby, respectively;

[0027]FIG. 7 is a block diagram illustrating an electrical makeup of thebiped walking robot shown in FIG. 1;

[0028]FIG. 8 schematically illustrates the biped walking robot of FIG. 1having a forward fall and taking a corrective action to have a safetyfall, specifically showing the robot before its fall at (A), having theforward fall at (B) and having the safety fall at (C); and

[0029]FIG. 9 schematically illustrates the biped walking robot of FIG. 1having a backward fall and taking a corrective action to have a safetyfall, specifically showing the robot before its fall at (A), having thebackward fall (B) and having the safety fall (C).

BEST MODES FOR CARRYING OUT THE INVENTION

[0030] Hereinafter, the present invention will be described in detailwith reference to suitable forms of embodiment thereof illustrated inthe drawing figures.

[0031]FIGS. 1 and 2 show how a biped walking humanoid robot according tothe present invention is constructed in one form of implementationthereof. Referring to FIG. 1, the biped walking robot indicated byreference character 10 includes a trunk 11 having a pair of legs 12L and12R attached to its lower part 11 b at a pair of opposite sides thereof,respectively, a pair of arms 13L and 13R attached to its upper part 11 aat a pair of opposite sides thereof, respectively, and a head 14attached to its upper end.

[0032] An anteflex region 11 c separates the upper and lower parts 11 aand 11 b of the trunk 11 from each other. The upper trunk part 11 a issupported pivotally at the anteflex region 11 c so as to be able toswing forth and back and especially to be able to bend forward. Thetrunk 11 contains a control means to be described later, and theanteflex region 11 c is constituted by a joint drive motor in suchmotors shown in and to be described in connection with FIG. 2.

[0033] Each of the legs 12L and 12R is made of an upper leg 15L, 15R, alower leg 16L, 16R, and a foot 17L, 17R. Here, each of the legs 12L and12R as shown in FIG. 2 has six (6) joint regions, namely stated in turnfrom upside, a waist joint region 18L, 18R for turning (pivotallymoving) the corresponding leg 12L, 12R relative to the trunk 11, a firsthip joint region 19L, 19R for turning the leg about a roll x-axis. asecond hip joint region 20L, 20R for turning the leg about a pitchy-axis, a joint region 22L, 22R at a knee 21L, 21R as a junction betweenthe upper leg 15L, 15R and the lower leg 16L, 16R for turning the lowerleg about a pitch axis, a first ankle joint region 23L, 23R for turningthe foot 17L, 17R about a pitch axis, and a second ankle joint region24L, 24R for turning the foot 17L, 17R about a roll axis.Each of thesejoint regions 18L, 18R˜24L, 24R is constituted as and by a joint drivemotor. It follows, therefore, that the waist/hip joints are constitutedby the joints 18L, 18R, 19L, 19R and 20L, 20R while the foot joints areby the joints 23L, 23R and 24L, 24R.

[0034] This makeup provides the six (6) degrees of freedom for each ofthe left and right hand side legs 12L, 12R of the biped walking humanoidrobot 10. The robot 10 is thus so configured that if these twelve (12)joint regions are adapted to be driven by the respective drive motors ina controlled manner to make proper angular movements such as to move thelegs 12L and 12R properly as a whole, the robot is rendered capable ofwalking in any way as desired in a three-dimensional space.

[0035] Each of the arms 13L and 13R is made of an upper arm 25L, 25R, alower arm 26L, 26R and a hand 27L, 27R. In each of the upper arm 25L,25R, the lower arm 26L, 26R and the hand 27L, 27R are each madepivotally movable monoaxially or biaxially as in each of the legs 12Land 12R. Each of the joint regions is constituted as and by a jointdrive motor. Given appropriate degrees of freedom in this manner, eachof the left and right hand arms 13L and 13R of the biped walkinghumanoid robot 10 is made movable as desired.

[0036] The head 14 which is mounted to the upper end of the upper trunkpart 11 a of the trunk body 11 is provided with a camera for vision anda microphone for audition.

[0037] The biped walking humanoid robot 10 of the invention constructedas mentioned above is essentially the same in makeup as the conventionalbiped walking humanoid robot but is novel and unique in makeup asmentioned below.

[0038] To wit, in the biped walking humanoid robot 10 of the inventionas illustrated, each of the upper and lower trunk parts 11 a and 11 b ofthe trunk body 11, the upper legs 15L and 15R and the lower legs 16L and16R of the legs 12L and 12R, and the upper arms 25L and 25R and thelower arms 26L and 26R of the arms 13L and 13R has a curved outercovering surface area that is convex or bulged in outline as shown inFIG. 1 and formed of an impact resistant material such as, for instance,styrofoam.

[0039] Further in the biped walking humanoid robot 10, each of thoseportions thereof which can strike against the floor or ground when therobot falls down, namely, an outer area of an elbow 28L, 28R formedbetween the upper arm 25L, 25R and the lower arm 26L, 26R of each of thearms 13L and 13R, an outer area of a wrist 29L, 29R formed between thelower arm 26L, 26R and the hand 27L, 27R of each of the arms 13L and13R, a central area of sole, a lower area of toe 30L, 30R and a lowerarea of heel 31L, 31R of each of the feet 17L and 17R, an outer area ofthe knee 21L, 21R of each of the legs 12L and 12R, and a surface area inthe rear 32 of the lower trunk part 11 b and a surface area in the rear33 of the upper trunk part 11 a of the trunk body 11 includes a contactdetector 40. The contact detector 40 as shown in FIG. 3 comprises anouter casing portion 41 of a material that constitutes the outercovering surface areas of the robot mentioned above, a pressure sensor42 disposed inwards of the outer covering portion 41 and an impactabsorbing material 43 disposed interiorly of the pressure sensor 42.

[0040] Such outer covering portions 41 are convex in contour and formedof an impact resistant material such as, for instance, styrofoam as arethe surface areas of the other parts of the robot mentioned above.

[0041] The pressure sensor 42 when the biped walking humanoid robot 10falls down or over is adapted to sense a contact pressure produced uponthe corresponding contact detector 40 forcibly coming into contact withthe floor or ground to provide a contact sensing signal for the controlmeans or stage to be described later.

[0042] The impact absorbing material made, e. g., of sorbothane isdesigned to absorb a shock which that contact detector 40 may receivefrom the floor or ground when the biped walking humanoid robot 10 fallsdown or over.

[0043] While the contact detector 40 is shown comprising, from outer toinner, the covering or casing portion 41, the pressure sensor 42 and theimpact absorbing material 42, they may be arranged in any order asdesired. In this connection it should be noted that disposing the casingportion 41 at the outermost side is advantageous in that when the bipedwalking humanoid robot 10 falls to cause the contact detector 40 to hiton the floor or ground, the casing 41 comes into direct contact with thefloor or ground, thereby protecting the pressure sensor 42, the impactresistant material 43 and further the inner structure of the robot fromthe shock. Disposing the pressure sensor 42 at the outermost side isadvantageous in that when the biped walking humanoid robot 10 falls, thepressure sensor 42 comes into direct contact with the floor or ground,thereby making most certain of sensing the pressure contact of thecontact detector 40 with the floor or ground. Disposing the impactabsorbing material 43 at the innermost side is advantageous in that whenthe biped walking humanoid robot 10 falls to cause the contact detector40 to hit on the floor or ground, the impact absorbing material comesinto direct contact with the floor or ground, thereby making for mostcertain of absorbing the shock.

[0044] Also, while the contact detector 40 is shown comprising thecasing portion 41, the pressure sensor 42 and the impact absorbingmaterial each separate from another, the casing portion 42 and theimpact absorbing material, or the casing portion 41, the pressure sensor42 and the impact absorbing material 43 may be made integral.

[0045] Further in the biped walking humanoid robot 10, the anteflexregion 11 c of the trunk body 11 and the joints front side back in thelegs 12L and 12R, namely the hip joints 20L and 20R, the knee joints 22Land 22R and the ankle joints 23L and 23R are individually made pivotablewithin angular limits as shown in FIGS. 4 and 5. To wit, the anklejoints 23L and 23R are each made pivotable in a rage of angles θ 1 from−20 to +20 degrees. The knee joints 22L and 22R are each made pivotablein a range of angles θ 2 from 0 to +60 degrees. The hip joints 20L and20R are each made pivotable in a range of angles θ 3 of 0 to +45degrees. The anteflex region 11c of the trunk body 11 is each madepivotable in a range of angles θ 4 from 0 to +30 degrees.

[0046] So that the anteflex region 11 c and the joints 20L, 20R, 22L,22R, 23L and 23R may be pivotable in those angular ranges, respectively,joint drive motors are provided for the anteflex region 11 c and thejoints 20L, 20R, 22L, 22R, 23L and 23R and arranged as shown in FIG. 6.Referring to FIG. 6, the joint drive motors M2, M3 and M4 for theanteflex region 11 c and the joints 20L, 20R, 22L, 22R, 23L and 23R havetheir respective drive shafts coupled via reducers G2, G3 and G4 totheir output shafts G2 a, G3 a and G4 a so as to drive the anteflexregion 11 c and the joints 20L, 20R, 22L, 22R, 23L and 23R, therebyswinging or pivotally moving the upper trunk 11 a of the trunk body, 11,the upper legs 15L and 15R, the lower legs 16L and 16R and the feet 17Land 17R about them, respectively. The motors M2, M3 and M4 including thereducers G2, G3 and G4, respectively, are disposed, as shown in FIG. 6A,inclined to one another so as not to hinder the pivotal movements at theanteflex region 11 c and the joints 20L, 20R, 22L, 22R, 23L and 23R.This arrangement prevents the motors M2, M3 and M4 as shown in FIG. 6Bfrom interfering with the swing motions or pivotal movements, wheneffected, at the anteflex region 11 c and the joints 20L, 20R, 22L, 22R,23L and 23R. With motors M2, M3 and M4 so arranged, therefore, withoutlengthening the legs 12L and 12R to an extent more than needed it isensured that the anteflex region 11 c and the joints 20L, 20R, 22L and22R can pivot each within a preestablished range of angles as needed.Shown further in FIG. 6 are joint drive motors M1 and M5 for the joints24L and 24R and the joints 19L and 19R, respectively.

[0047] Referring next to FIG. 7 which shows the electrical makeup of thebiped walking humanoid robot shown in FIGS. 1 to 6, there is shown awalk controller 50 for controlling the driving actions of the drivemeans, namely the drive motors for the anteflex region 11 c, and thejoints 18L, 18R to 24L and 24R.

[0048] The controller 50 comprises a control stage 51 and a motorcontrol unit 52. The control stage 51 is designed to form a controlsignal for each of the joint drive motors on the basis of apreestablished gait pattern. The motor control unit 52 is designed todrive each of the joint drive motors controllably in accordance with acontrol signal from the control stage 51. Further, the control stage 51when the biped walking humanoid robot 10 is falling is so designed thatit is responsive to contact sensing signals from the pressure sensors 42of the contact detectors 40 to determine a type of the fall the robot isthen having. The control stage 51 is then designed to form controlsignals for the joint drive motors so that the robot 10 takes apreestablished safety fall and thereafter a preestablished rising actionor motion pattern.

[0049] Constructed as mentioned above, the biped walking humanoid robot10 according to the illustrated form of implementation of the inventionis actuated to walk normally when the joint drive motors for theanteflex region 11 c, and the joints 18L, 18R to 24L and 24R arecontrollably driven by the motor control unit 52 furnished with controlsignals formed at the control stage 51 in the walk controller 50 on thebasis of a preestablished gait pattern.

[0050] However, the biped walking humanoid robot 10 may become unstablein its walking posture and might then be falling forward. As far as therobot 10 is walking normally as shown in FIG. 8A, the pressure sensor inthe contact detector 40 mounted at a center region of the sole of eachof the feet 17L and 17R provides a pressure signal for the control stage51 which in turn judges that the robot is walking stably to allow it tocontinue to walk.

[0051] If the biped humanoid robot is falling forward as shown in FIG.8B, the pressure sensor in the contact detector 40 mounted at the wrist29L, 29R of one of the arms 13L and 13R responds to this and provides acontact signal for the control stage 51 which in turn judges that therobot is falling forward and provides the motor control unit 52 withcontrol signals such as to cause the robot 10 to take a correctivefalling action to have a safety fall with both the elbows 28L and 28Rand both the knees 21L and 21R on the floor or ground as shown in FIG.8C. Further, any shock acting on each of the elbows 28L and 28R and theknees 21L and 21R when it hits on the floor or ground is absorbed by theimpact absorbing element 43 in the contact detector 40 mounted in eachof these robot's parts.

[0052] Furthermore, furnished with contact signals from the contactdetectors 40 mounted in both elbows 28L and 28R, both knees 21L and 21Rand the toe 30L or 30R of one foot 17L or 17R which are all brought intocontact with the floor or ground, the control stage 51 can accuratelydetermine an exact posture of the fall the robot 10 has. Hence, it canprovide the motor control unit 52 with control signals such as to causethe robot 10 to take a rising action to get up on its feet. Then,provided with its cladding surfaces of the parts individually convex incontour, the robot 10 is allowed to make the successive rising movementssmoothly.

[0053] The biped walking humanoid robot 10 becoming unstable in itswalking posture might also be falling backward. As far as the robot 10is walking normally as shown in FIG. 9A, the pressure sensor in thecontact detector 40 mounted at the center region of the sole of each ofthe feet 17L and 17R provides a pressure signal for the control stage 51which in turn judges that the robot is walking stably to allow it tocontinue to walk.

[0054] If the biped humanoid robot is falling backward as shown in FIG.9B, the pressure sensor 42 in the contact detector 40 mounted at theheel 31L, 31R of one of the feet 17L and 17R responds to this andprovides a contact signal for the control stage 51 which in turn judgesthat the robot is falling backward and provides the motor control unit52 with control signals such as to cause the robot 10 to take acorrective action to have a safety fall with the behind 32, the back 33and both elbows 28L and 28R on the floor or ground as shown in FIG. 8C.Further, any shock acting on each of the behind 32, the back 33 and bothelbows 28L and 28R when it hits on the floor or ground is absorbed bythe impact absorbing element 43 in the contact detector 40 mounted ineach of these robot's parts.

[0055] Furthermore, furnished with contact signals from the contactdetectors 40 mounted in the behind 32, the back 33 and both elbows 28Land 28R which are all brought into contact with the floor or ground, thecontrol stage 51 can accurately determine an exact posture of the fallthe robot 10 has. Hence, it can provide the motor control unit 52 withcontrol signals such as to cause the robot 10 to take a rising action toget up on its feet. Then, provided with its cladding surfaces of theparts individually convex in contour, the robot 10 is allowed to makethe successive rising movements smoothly.

[0056] Thus, provided at elbows 28L and 28R, wrists 29L and 29R, theknees 21L, 21R and a center region, heel 31L, 31R and toe 30L, 30R ofthe sole of each of feet 17L and 17R with contact detectors 40 whichpermit detecting the posture of a fall that it may have, a biped walkinghumanoid robot 10 of the present invention as illustrated is allowed totake a corrective falling action to have a safety fall and then tosmoothly shift to taking a rising action to get up on the feet, thecorrective falling and rising actions meeting with the falling posturedetected. Further, given the ability to grasp the posture of its fall, abiped walking humanoid robot 10 of the invention as illustrated is evencapable of performing a forward and a backward roll in the course thatit is falling to rise on its feet.

[0057] While in the foregoing description mention is not made of how thearms 13L and 13R should be moved when the robot is taking a correctivefalling and a rising action, it should be obvious that they may then bemoved in any suitable way.

INDUSTRIAL APPLICABILITY

[0058] There is provided in accordance with the present invention abiped walking humanoid robot in which a contact detector having animpact absorbing material is disposed at each of those parts of therobot which can hit on the floor or ground when the robot is fallingdown to or rolling over it, namely, at each of an outer area of an elbowportion formed between the upper and lower arm portions, and an outerarea of a wrist portion formed between the lower arm portion and thehand portion of each of the arm portions, and a lower side of a toeformed in the foot portion, a lower side of a heel portion formed in thefoot portion, and an outer area of a knee portion formed between theupper and lower leg portions of each of the leg portions, and a hipregion and a back region of the body portion whereby any shock acting onany of these parts hitting on the floor or ground can be absorbed by theimpact absorbing material. With the shock against the internal structureof each of these parts so alleviated, they are protected from anypossible damage that should otherwise be the case when the biped walkinghumanoid robot happens to fall to or is attempting to perform a rollingaction over the floor or ground.

[0059] And, when the biped walking humanoid robot is having a fall, thestate or type of this fall can be determined by a control means inresponse to a contact signal detected by the pressure sensor in thecontact detector at a relevant part of the abovementioned robot partswhich is brought into contact with the floor or ground. Then, on thebasis of the type of the fall determined, the control means is allowedto act on the drive means to move the arm and leg parts suitably so asto cause the robot to take a corrective falling action to have a safetyfall and then to move to taking a rising action to get up on its feet.

[0060] There is thus provided a biped walking humanoid robot which soeminently excels that shocks acting on various parts of the robot whenit falls can be relieved and its state or type of fall can then bedetected.

What is claimed is:
 1. A biped walking humanoid robot, comprising: abody portion having an upper and a lower part, a pair of leg portionsattached to the lower part of the body portion at a pair of its oppositesides, respectively, a pair of arm portions attached to the upper partof the body portion at a pair of its opposite sides, respectively, and ahead portion attached to an upper end of the upper part of the bodyportion, wherein each of the leg portions includes two upper legportions attached to the lower part of the body portion so as to bepivotally movable relative thereto triaxially, a lower leg portionattached to the upper leg portion so as to be pivotally movable relativethereto monoaxially, and a foot portion attached to the lower legportion so as to be pivotally movable relative thereto biaxially,wherein each of the arm portions includes tow upper arms portionattached to the upper part of the body portion so as to be pivotallymovable relative thereto biaxially, a lower arm portion attached to theupper arm portion so as to be pivotally movable relative theretomonoaxially, and a hand portion attached to the lower arm portion so asto be pivotally movable relative thereto biaxially, wherein the bodyportion has an intermediate, anteflex region at which it is made able tobend forward; and wherein the robot further comprises a drive means forpivotally moving each of the foot portion, the lower leg portion and theupper leg portion of each of the leg portions, and the hand portion, thelower arm portion and the upper arm portion of each of the arm portions,and the body portion at the anteflex region, and a control means forcontrolling driving actions of the drive means; the robot beingcharacterized in that: there is provided a contact detector at each ofan outer area of an elbow portion formed between the upper and lower armportions, and an outer area of a wrist portion formed between the lowerarm portion and the hand portion of each of said arm portions, and alower side of a toe portion formed in the foot portion, a lower side ofa heel portion formed in the foot portion, and an outer area of a kneeportion formed between the upper and lower leg portions of each of saidleg portions, and a hip region and a back region of said body portion,and said contact detector comprises a casing portion forming an outercovering surface of the robot at said contact detector, a pressuresensor for sensing a pressure acting on said casing portion and animpact absorbing material for relieving a shock acting on said casingportion.
 2. A biped walking humanoid robot as set forth in claim 1,characterized in that in each of such contact detectors said pressuresensor and said impact absorbing material are integrally formed.
 3. Abiped walking humanoid robot as set forth in claim 1, characterized inthat in each of such contact detectors said casing portion, saidpressure sensor and said impact absorbing material are formedintegrally.
 4. A biped walking humanoid robot as set forth in claim 1,characterized in that in each of such contact detectors said casingportion lies at an outermost side thereof.
 5. A biped walking humanoidrobot as set forth in claim 1, characterized in that in each of suchcontact detectors said pressure sensor lies at an outermost sidethereof.
 6. A biped walking humanoid robot as set forth in claim 1,characterized in that in each of such contact detectors said impactabsorbing material lies at an outermost side thereof.
 7. A biped walkinghumanoid robot as set forth in claim 1, characterized in that each ofsaid body portion, the upper and lower arm portions of said armportions, and the upper and lower leg portions of said leg portions hasa curved outer covering surface that is convex in contour.
 8. A bipedwalking humanoid robot as set forth in claim 1, characterized in that:for each of said leg portions said foot portion is made pivotallymovable relative to said lower leg portion in a pitch direction in arange of angles from −20 to +20 degrees or more, said lower leg portionis made pivotally movable relative to said upper leg portion in a pitchdirection in an range of angles from 0 to +60 degrees or more, and saidupper leg portion is made pivotally movable relative to said bodyportion in a pitch direction in a range of angles from 0 to +45 degreesor more, and said body portion is made able to bend forward in a rangeof angles from 0 to +30 degrees or more.
 9. A biped walking humanoidrobot as set forth in claim 1, characterized in that those of said drivemeans for pivotally moving the foot portion, the lower leg portion andthe upper leg portion of each of said leg portions, respectively, aredisposed inclined to one another so as not to hinder pivotal movementsof said foot portion, said upper leg portion and said lower leg portion.